deepseek-ai/DeepSeek-V4-Flash-0731

DeepSeek-V4-Flash-0731

Technical Report👁️

Introduction

DeepSeek-V4-Flash-0731 is the official release of DeepSeek-V4-Flash, superseding the preview version, with substantially enhanced agentic capabilities. It has the same model structure as DeepSeek-V4-Flash-DSpark, i.e. it comes with a speculative decoding module attached.

DeepSeek-V4-Flash-0731 outperforms DeepSeek-V4-Pro (Preview) on benchmarks listed below despite its far smaller activated parameter count, and is broadly competitive with the strongest proprietary models available.

| Benchmark | DeepSeek-V4-Flash-0731 | DeepSeek-V4-Flash (Preview) | DeepSeek-V4-Pro (Preview) | GLM-5.2 | Opus-4.8 | | :--- | :---: | :---: | :---: | :---: | :---: | | Terminal Bench 2.1 | 82.7 | 61.8 | 72.1 | 81.0 | 85.0 | | NL2Repo | 54.2 | 39.4 | 38.5 | 48.9 | 69.7 | | Cybergym | 76.7 | 38.7 | 52.7 | - | 83.1 | | DeepSWE | 54.4 | 7.3 | 12.8 | 46.2 | 58.0 | | Toolathlon-Verified | 70.3 | 49.7 | 55.9 | 59.9 | 76.2 | | Agents' Last Exam | 25.2 | 15.8 | 16.5 | 23.8 | 25.7 | | AutomationBench Public | 25.1 | 10.8 | 12.8 | 12.9 | 27.2 | | DSBench-FullStack † | 68.7 | 37.0 | 41.8 | 61.8 | 71.6 | | DSBench-Hard † | 59.6 | 25.8 | 31.1 | 54.5 | 71.7 |

Notes:

1. For the Code Agent tasks among the public benchmarks above, DeepSeek-V4-Flash-0731 is evaluated with the minimal mode of DeepSeek Harness (to be released) as the agent framework, using the max reasoning effort level with temperature = 1.0, top_p = 0.95. 2. † DSBench-FullStack is an internal full-stack development test set; DSBench-Hard is an internal test set of difficult coding-agent problems.

Chat Template

This release does not include a Jinja-format chat template. Instead, we provide a dedicated encoding folder with Python scripts and test cases demonstrating how to encode messages in OpenAI-compatible format into input strings for the model, and how to parse the model's text output. Please refer to the encoding folder for full documentation.

The reasoning_effort parameter now supports three levels — low, high, and max — which control how much deliberation the model spends before answering.

A brief example:

```python from encoding_dsv4 import encode_messages, parse_message_from_completion_text

messages = [ {"role": "user", "content": "hello"}, {"role": "assistant", "content": "Hello! I am DeepSeek.", "reasoning_content": "thinking..."}, {"role": "user", "content": "1+1=?"} ]

messages -> string

prompt = encode_messages(messages, thinking_mode="thinking", reasoning_effort="max")

string -> tokens

import transformers tokenizer = transformers.AutoTokenizer.from_pretrained("deepseek-ai/DeepSeek-V4-Flash-0731") tokens = tokenizer.encode(prompt) ```

How to Run with vLLM

DSpark speculative decoding is enabled with a single flag — add --speculative-config with method: dspark to your vLLM launch command:

--speculative-config '{"method":"dspark","num_speculative_tokens":7,"draft_sample_method":"greedy"}'

For example, the command below serves the model with vLLM on a single 4×GB300 node. See the vLLM recipe for detailed instructions and other hardware configurations.

``bash vllm serve deepseek-ai/DeepSeek-V4-Flash-0731 \ --trust-remote-code --kv-cache-dtype fp8 --block-size 256 \ --data-parallel-size 4 --enable-expert-parallel \ --moe-backend deep_gemm_mega_moe \ --attention-config '{"use_fp4_indexer_cache": true}' \ --speculative-config '{"method":"dspark","num_speculative_tokens":7,"draft_sample_method":"greedy"}' ``

How to Run with SGLang

Enable DSpark with --speculative-algorithm DSPARK and do not set a separate --speculative-draft-model-path as the target and draft weights therefore come from the same checkpoint. See the SGLang cookbook for detailed instructions, benchmarks and other hardwares configurations.

``bash sglang serve \ --trust-remote-code \ --model-path deepseek-ai/DeepSeek-V4-Flash-0731 \ --tp 4 \ --moe-runner-backend flashinfer_mxfp4 \ --speculative-algorithm DSPARK \ --mem-fraction-static 0.90 \ --chunked-prefill-size 4096 \ --swa-full-tokens-ratio 0.1 \ ``

How to Run Locally

Please refer to the inference folder for detailed instructions on running DeepSeek-V4 locally, including model weight conversion and interactive chat demos.

For local deployment, we recommend setting the sampling parameters to temperature = 1.0, with top_p = 0.95 for agentic scenarios and top_p = 1.0 otherwise. For the high and max reasoning effort levels, we recommend a maximum output length of 384K tokens.

License

This repository and the model weights are licensed under the MIT License.

Citation

`` @misc{deepseekai2026deepseekv4, title={DeepSeek-V4: Towards Highly Efficient Million-Token Context Intelligence}, author={DeepSeek-AI}, year={2026}, } ``

Contact

If you have any questions, please raise an issue or contact us at [email protected].